The present invention relates to 4-alkoxy-3,5-diamino-.alpha.,.alpha.,.alpha.-trifluoromethylbenzene and a manufacture thereof and a hardener for polyurethane elastomer thereof.
It has been known that aromatic diamines are used as hardeners for polyurethane elastomers. Various aromatic diamines have been proposed.
However, satisfactory aromatic diamines could not be obtained because of the various requirements needed in a hardener for polyurethane elastomers.
The important factors required for the hardener are as follows.
Firstly, it should be a low melting point solid or liquid from the viewpoints of processability, labour hygiene and energy saving.
Secondly, a pot life from the time of mixing hardener with a mixture of polyisocyanate and polyol or a prepolymer having the terminal isocyanate group to non-flowing the mixture for casting, should be suitable.
Thirdly, a set time of the demoldable time from molding to demolding from the viewpoint of processability especially efficiency.
Fourthly, the object hardener should be easily produced and be stable.
Fifth, the resulting polyurethane elastomer should have excellent physical properties.
However, these requirements are contradictory for example, if a short set time is required, the pot life is shortened to cause a trouble in the processing. Accordingly, it is difficult to obtain a hardener having satisfactory and balanced characteristics.
3,3'-Dichloro-4,4'-diaminodiphenylmethane is a known hardener for polyurethane elastomer having excellent physical characteristics, however, it has the disadvantage of high melting point which cause inferior processability.
4-Chloro-3,5-diamino-.alpha.,.alpha.,.alpha.-trifluoromethylbenzene has long pot life but it has long set time and a polyurethane elastomer having inferior physical characteristic is obtained, disadvantageously.
The inventors have studied on syntheses of various compounds for finding hardeners having satisfactory characteristics for polyurethane elastomers.